1. Field of the Invention
The present invention relates to a wheelchair with a chair part and wheels provided on both sides of the chair part, allowing a user who sits on the chair to move himself by rotating the wheels using his own hands.
2. Description of the Related Art
A current used wheelchair has a wheel which fixes a hub via spokes on a rim fixing a tire around thereon, and a metal ring is fixed on the outer side of the rim. The metal ring has a smaller diameter than the tire, and is spaced apart from the rim to permit it to be easily grasped to drive the wheel. To separate the metal ring from the rim, the metal ring is fixed by arm located in a predetermined space in order to fix the rim.
In use of the wheelchair having this construction, a user grasps the metal ring and rotates the wheel. But the users hand can hit the arm causing pain and discomfort. To prevent his hand from hitting the arm while driving the wheel, it is necessary for user to keep his hand away from the metal ring after he rotates the wheel by grasping the metal ring. It is impossible to drive the wheel by keeping his hand on or around the metal ring.
To prevent this drawback, another wheelchair was developed in which a disk is fixed on the outside of the wheel (see Japanese Patent Laid Open No. 11-347072). The wheelchair disclosed in this reference has a disk 41 fixed on the outside of the wheel 40, and a protruding portion 42 is provided on an outer periphery of the disk 41 to permit it to be gripped by hand.
The wheel 40 for the wheelchair shown in FIG. 1 is used to drive the wheel 40 by grasping the protruding portion 42 of the disk 41 that is fixed outward of the wheel 40. Since this wheel 40 with this structure has such drawbacks that it easily slips since the protruding portion 42 on the wheel 40 is gripped on both the upper side and the lower side by hand. Further, if a user grips protruding portion 42 hard to prevent slipping, then his hand gets fatigued easily. Moreover, the wheel 40 with such construction has the disk 41 fixed to the rim 43 and the protruding portion 42 protrudes outwardly from this disk 41. This configuration causes a wider size of the whole wheel, and it would be difficult to move in a small room smoothly because of the wide side. Also, another wheelchair in the related art having a wheel with a metal ring has similar drawbacks, i.e., its metal ring protrudes outwardly, thereby resulting in a wider size of the wheel. Also, it would be difficult to smoothly move in the small room.